1 NOTE: An error in the 1960 rural population count was discovered after the publication of CPH-2-1 from the 1990 Census. 2  The correct 1960 rural population using the 'Current urban definition' is 54,054,425.
Tyr (-5). Phe (-5). Role in structure: Glycine is a very unique amino acid in that in contains a hydrogen as its side chain (rather than a carbon as is the case in all other amino acids). This means that there is much more conformational flexibility in glycine.
Glycine's function as a neurotransmitter is also fairly simple. When released into a synapse, glycine binds to a receptor which makes the post-synaptic membrane more permeable to Cl- ion. This hyperpolarizes the membrane, making it less likely to depolarize. Thus, glycine is an inhibitory neurotransmitter. It is de-activated in the synapse by a simple process of reabsorption by active transport back into the pre-synaptic membrane. Glycine is a neurotransmitter only in vertebrate animals.